In-Source Fragmentation of Very Labile Peptides in Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

Printer-friendly version
TitleIn-Source Fragmentation of Very Labile Peptides in Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry
Publication TypeJournal Article
Year of Publication2009
AuthorsSachon, E, Clodic G, Blasco T, Jacquot Y, Bolbach G
JournalAnalytical Chemistry
Volume81
Issue21
Pagination8986-8992
Date PublishedNov
ISBN Number0003-2700
Accession NumberISI:000276191900048
Abstract

Synthetic acidic proline-rich peptides devoid of basic chemical groups were studied by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF). Their ion mass spectra recorded in reflector positive ion mode have shown unusual features, i.e., absence or very weak presence of protonated peptide together with a major peak associated with fragmentation at a site that corresponds to the amide bond N-terminal to the first proline of the XPP motif. In contrast, arginine-containing analogues were stable in MALDI-TOF, whereas peptides sharing a free N-terminal amino group were moderately subject to the same fragmentation. Effects of extraction delay time suggest that this process takes place very early (nanoseconds) at the beginning of the plume expansion. The effect of the nature of the matrix on the survival yield indicates a better correlation with the initial axial velocity than with the matrix proton affinity. All the data show some strong differences with the classical in-source decay (ISD). Our results suggest the role of the available protons in the close neighborhood of the peptide during the crystallization process and the prompt fragmentation induced by collisions in the first step of ablation. Undoubtedly, our study highlights that the MALDI-TOF analysis of peptides containing proline and no basic group should be carried out with extreme caution.

URL<Go to ISI>://000276191900048
DOI10.1021/ac901449d
Short TitleIn-Source Fragmentation of Very Labile Peptides in Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry
Unit: 
Departement